In marine seismic geophysical data acquisition is employed one, two or more parallel streamer cables, i.e. hydrophone cables which are towed as a streamer cable array after a vessel. If there are two or more parallel streamer cables being towed as a streamer cable array behind a vessel it is common to use starboard and port deflector paravanes which span out the fore end of the streamer cable array so as for the streamer cables to run parallel and with a desired spanned mutual separation. The streamer cables are 2-10 km of length and their mutual separation may be 25 to 150 m.
Starboard deflector comprises a longitudinally running float of about 10 m length, the length of floats varies depending on the requirements, and down from the float extend vertical deflector wings having an aircraft wing profile and are arranged so as for pulling outward relative the vessel's course line. The deflector wings are held fixed by an upper horizontal plate which resides just below the float, and a lower horizontal plate, and there is likely arranged a horizontal plate in a middle level, too. Bridle lines from the fore and aft portions of the horizontal plates are joined in a bridle block. A bridle block, please see FIG. 1, usually comprise bearing sleeves for the eyelets of the bridle lines on two triple heads on a pair of arms extending from a hinge bearing block with a hinge pin which forms an apex for the six bridle lines. The hinge pin, and thereby the bridle block, is further connected directly or indirectly via a sheave to an eyelet of a towing line. There are load cells on the hinge pin for measuring the force between the towing line and the bridle block. This force is important for monitoring during towing the deflector and thus the entire array, and is not necessarily equal to the towing force as measured from the vessel, as the towing line is strongly affected by its running through the seas through which it runs obliquely abaft of the beam extending to starboard and port side. Particularly during a U-turn from one course to an opposite course the force on the deflector running in the outer lane. The load cells are connected via at least one signal cable laid about one of the bridle lines' bearing sleeves and out along one of the bridle lines, please see FIG. 1.
A problem of the background art is the crane handling upon launching and hauling the deflector, and particularly when changing from lifting by the towing line to gripping the deflector, and oppositely. The bridle block is particularly designed for the dynamic loads which are due to towing after the towing line and is not particularly suited for being gripped by means of a crane, and is thus vulnerable. Another problem is that the cable to the load cells, because it runs outside the bridle block, please see FIG. 1, and is vulnerable during such handling as this may easily be torn off or damaged during handling with crane, wires, lifting yokes or ropes. A damage to the bridle block or the cable to the load cells during handling will incur significant delays particularly during launching of the deflector. A damage to the bridle block will immediately be visible; a damage to the load cell may possibly not be discovered before one is about to measure the pulling load after the array has been spanned out.
EP2420866 discloses a connecting device for wide tow seismic survey where the bridles are comprising at least one solid link or connection device for releasable connection to lines under tension and extending in different directions.